Vibration at speeds above 70MPH

Hello,

My 2014 Grand Cherokee, 5.7L, RWD, Limited, has been exhibiting a vibration noticeable in the steering wheel as well as in the floor of the vehicle at highway speeds ever since I got it in 2013.

It had new tires, brakes (including rotors), rotations, and even new specific part number wheel hubs (front) put on (per the bulletin I found). The issue persisted.

At first I believed the vibration was only in the steering wheel, because it was too difficult to notice anything beyond that. But I eventually noticed that I can also feel and even hear vibration in the rest of the vehicle especially when I have something loose in the trunk.

At this point I am thinking driveshaft, but after those expensive hubs I am not keen on just tossing money at it without asking for advice first.

The vibration used to be bad only between 72 and 80 MPH (going with flow of traffic :) ). Now I believe it only changes frequency but doesn't go away at higher speed. Also noticed that on first drive of a cold day vibration is worse, more aggressive, at least in the steering wheel.

Throwing the car in Neutral doesn't change vibration. Vibration occurs whether i am accelerating, coasting or decelerating.

In the days of heavy traffic I rarely got it up to the vibration speeds. Since 2020, and now being a bit out of the city, it is an issue I experience every time I am on a freeway.

Any help/direction would be highly appreciated.

Igor.